package com.web.new12306.controller;  
  
import java.io.IOException;  
  
import javax.servlet.ServletException;  
import javax.servlet.http.HttpServlet;  
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpServletResponse;  
import javax.servlet.http.HttpSession;  
  
public class LogoutServlet extends HttpServlet {  
  
 /** 
 * @category 退出登录的Servlet,注销 
 * @author 苗宇
 *
 */
    private static final long serialVersionUID = 1L;  
  
    public void doGet(HttpServletRequest request, HttpServletResponse response)  
            throws ServletException, IOException {  
    	   doPost(request, response);
    }  
  
    public void doPost(HttpServletRequest request, HttpServletResponse response)  
            throws ServletException, IOException { 
    	
        HttpSession session = request.getSession(false);//防止创建Session  
        if(session == null){    
        	response.sendRedirect(request.getContextPath() + "/userLogin.jsp");
            return;  
        }  
          
        session.removeAttribute("user");  
    	response.sendRedirect(request.getContextPath() + "/userLogin.jsp");
  
    }  
  
}  
		
		
		
		
	